Omron EasySpeed 3G3JE, User Manual, Page: 121 / 133

Chapter 7
7-3
Appendix
● Rotary Drive Application: Normal Power P0 (kW)
T
l
: Load torque (load axis, N·m)
N
l
: Load axis speed (r/min)
η
: Efficiency of transmission mechanism (
η ≤
1)
■ Detailed Selection Method: RMS Calculations
With this method, the motor is selected by calculating the effective torque and maximum torque
required to achieve the application's operating pattern based on the output (kW) required for the
motor's normal steady-state operation. This method can be used to select the motor appropriate for
an operating pattern.
● Calculating the Load Inertia and Motor Axis Inertia
Calculate the moment of inertia at the motor axis by calculating the moment of inertia of all of the
parts including the power transmission system.
Winder Example
Jw: Axial inertia (kg·m
2
)
J1: Cylindrical inertia (axial, kg·m
2
)
J2: Workpiece inertia (axial, kg·m
2
)
M1: Cylinder weight (kg)
M2: Workpiece weight (kg)
D: Cylinder diameter (mm)
P
0
(kW) =
×
10
−
3
2
π
·T
l
·N
l
60·
η
T
l
η
Motor
N
l
=
+
×
10
−
6
M1·D
2
8
M2·D
2
4
D
M1
J
w
M2
J
w
(kg·m
2
)
= J
1
+ J
2